diff --git a/apps/bench.py b/apps/bench.py
index 4708403..8b37883 100644
--- a/apps/bench.py
+++ b/apps/bench.py
@@ -24,6 +24,7 @@ import time
 
 import click
 
+from bumble import l2cap
 from bumble.core import (
     BT_BR_EDR_TRANSPORT,
     BT_LE_TRANSPORT,
@@ -85,6 +86,7 @@ DEFAULT_LINGER_TIME = 1.0
 
 DEFAULT_RFCOMM_CHANNEL = 8
 
+
 # -----------------------------------------------------------------------------
 # Utils
 # -----------------------------------------------------------------------------
@@ -197,6 +199,7 @@ class PacketType(enum.IntEnum):
 
 PACKET_FLAG_LAST = 1
 
+
 # -----------------------------------------------------------------------------
 # Sender
 # -----------------------------------------------------------------------------
@@ -659,17 +662,19 @@ class L2capClient(StreamedPacketIO):
         self.mps = mps
         self.ready = asyncio.Event()
 
-    async def on_connection(self, connection):
+    async def on_connection(self, connection: Connection) -> None:
         connection.on('disconnection', self.on_disconnection)
 
         # Connect a new L2CAP channel
         print(color(f'>>> Opening L2CAP channel on PSM = {self.psm}', 'yellow'))
         try:
-            l2cap_channel = await connection.open_l2cap_channel(
-                psm=self.psm,
-                max_credits=self.max_credits,
-                mtu=self.mtu,
-                mps=self.mps,
+            l2cap_channel = await connection.create_l2cap_channel(
+                spec=l2cap.LeCreditBasedChannelSpec(
+                    psm=self.psm,
+                    max_credits=self.max_credits,
+                    mtu=self.mtu,
+                    mps=self.mps,
+                )
             )
             print(color('*** L2CAP channel:', 'cyan'), l2cap_channel)
         except Exception as error:
@@ -695,7 +700,7 @@ class L2capClient(StreamedPacketIO):
 class L2capServer(StreamedPacketIO):
     def __init__(
         self,
-        device,
+        device: Device,
         psm=DEFAULT_L2CAP_PSM,
         max_credits=DEFAULT_L2CAP_MAX_CREDITS,
         mtu=DEFAULT_L2CAP_MTU,
@@ -706,12 +711,11 @@ class L2capServer(StreamedPacketIO):
         self.ready = asyncio.Event()
 
         # Listen for incoming L2CAP CoC connections
-        device.register_l2cap_channel_server(
-            psm=psm,
-            server=self.on_l2cap_channel,
-            max_credits=max_credits,
-            mtu=mtu,
-            mps=mps,
+        device.create_l2cap_server(
+            spec=l2cap.LeCreditBasedChannelSpec(
+                psm=psm, mtu=mtu, mps=mps, max_credits=max_credits
+            ),
+            handler=self.on_l2cap_channel,
         )
         print(color(f'### Listening for CoC connection on PSM {psm}', 'yellow'))
 
diff --git a/apps/gg_bridge.py b/apps/gg_bridge.py
index 88ebdc5..12d16e4 100644
--- a/apps/gg_bridge.py
+++ b/apps/gg_bridge.py
@@ -21,6 +21,7 @@ import struct
 import logging
 import click
 
+from bumble import l2cap
 from bumble.colors import color
 from bumble.device import Device, Peer
 from bumble.core import AdvertisingData
@@ -204,7 +205,7 @@ class GattlinkHubBridge(GattlinkL2capEndpoint, Device.Listener):
 
 # -----------------------------------------------------------------------------
 class GattlinkNodeBridge(GattlinkL2capEndpoint, Device.Listener):
-    def __init__(self, device):
+    def __init__(self, device: Device):
         super().__init__()
         self.device = device
         self.peer = None
@@ -218,7 +219,12 @@ class GattlinkNodeBridge(GattlinkL2capEndpoint, Device.Listener):
 
         # Listen for incoming L2CAP CoC connections
         psm = 0xFB
-        device.register_l2cap_channel_server(0xFB, self.on_coc)
+        device.create_l2cap_server(
+            spec=l2cap.LeCreditBasedChannelSpec(
+                psm=0xFB,
+            ),
+            handler=self.on_coc,
+        )
         print(f'### Listening for CoC connection on PSM {psm}')
 
         # Setup the Gattlink service
diff --git a/apps/l2cap_bridge.py b/apps/l2cap_bridge.py
index 83379a0..14bd759 100644
--- a/apps/l2cap_bridge.py
+++ b/apps/l2cap_bridge.py
@@ -20,6 +20,7 @@ import logging
 import os
 import click
 
+from bumble import l2cap
 from bumble.colors import color
 from bumble.transport import open_transport_or_link
 from bumble.device import Device
@@ -47,14 +48,13 @@ class ServerBridge:
         self.tcp_host = tcp_host
         self.tcp_port = tcp_port
 
-    async def start(self, device):
+    async def start(self, device: Device) -> None:
         # Listen for incoming L2CAP CoC connections
-        device.register_l2cap_channel_server(
-            psm=self.psm,
-            server=self.on_coc,
-            max_credits=self.max_credits,
-            mtu=self.mtu,
-            mps=self.mps,
+        device.create_l2cap_server(
+            spec=l2cap.LeCreditBasedChannelSpec(
+                psm=self.psm, mtu=self.mtu, mps=self.mps, max_credits=self.max_credits
+            ),
+            handler=self.on_coc,
         )
         print(color(f'### Listening for CoC connection on PSM {self.psm}', 'yellow'))
 
@@ -195,11 +195,13 @@ class ClientBridge:
             # Connect a new L2CAP channel
             print(color(f'>>> Opening L2CAP channel on PSM = {self.psm}', 'yellow'))
             try:
-                l2cap_channel = await connection.open_l2cap_channel(
-                    psm=self.psm,
-                    max_credits=self.max_credits,
-                    mtu=self.mtu,
-                    mps=self.mps,
+                l2cap_channel = await connection.create_l2cap_channel(
+                    spec=l2cap.LeCreditBasedChannelSpec(
+                        psm=self.psm,
+                        max_credits=self.max_credits,
+                        mtu=self.mtu,
+                        mps=self.mps,
+                    )
                 )
                 print(color('*** L2CAP channel:', 'cyan'), l2cap_channel)
             except Exception as error:
diff --git a/apps/speaker/speaker.py b/apps/speaker/speaker.py
index e451c04..84e05a0 100644
--- a/apps/speaker/speaker.py
+++ b/apps/speaker/speaker.py
@@ -641,7 +641,7 @@ class Speaker:
             self.device.on('connection', self.on_bluetooth_connection)
 
             # Create a listener to wait for AVDTP connections
-            self.listener = Listener(Listener.create_registrar(self.device))
+            self.listener = Listener.for_device(self.device)
             self.listener.on('connection', self.on_avdtp_connection)
 
             print(f'Speaker ready to play, codec={color(self.codec, "cyan")}')
diff --git a/bumble/l2cap.py b/bumble/l2cap.py
index 749f0d3..7a2f0ed 100644
--- a/bumble/l2cap.py
+++ b/bumble/l2cap.py
@@ -1036,9 +1036,11 @@ class LeCreditBasedChannel(EventEmitter):
     out_queue: Deque[bytes]
     connection_result: Optional[asyncio.Future[LeCreditBasedChannel]]
     disconnection_result: Optional[asyncio.Future[None]]
+    in_sdu: Optional[bytes]
     out_sdu: Optional[bytes]
     state: State
     connection: Connection
+    sink: Optional[Callable[[bytes], Any]]
 
     def __init__(
         self,
@@ -1525,7 +1527,7 @@ class ChannelManager:
         if cid in self.fixed_channels:
             del self.fixed_channels[cid]
 
-    @deprecated("Please use create_classic_channel_server")
+    @deprecated("Please use create_classic_server")
     def register_server(
         self,
         psm: int,
@@ -1540,7 +1542,7 @@ class ChannelManager:
         spec: ClassicChannelSpec,
         handler: Optional[Callable[[ClassicChannel], Any]] = None,
     ) -> ClassicChannelServer:
-        if spec.psm is None:
+        if not spec.psm:
             # Find a free PSM
             for candidate in range(
                 L2CAP_PSM_DYNAMIC_RANGE_START, L2CAP_PSM_DYNAMIC_RANGE_END + 1, 2
@@ -1592,7 +1594,7 @@ class ChannelManager:
         spec: LeCreditBasedChannelSpec,
         handler: Optional[Callable[[LeCreditBasedChannel], Any]] = None,
     ) -> LeCreditBasedChannelServer:
-        if spec.psm is None:
+        if not spec.psm:
             # Find a free PSM
             for candidate in range(
                 L2CAP_LE_PSM_DYNAMIC_RANGE_START, L2CAP_LE_PSM_DYNAMIC_RANGE_END + 1
diff --git a/bumble/profiles/asha_service.py b/bumble/profiles/asha_service.py
index 6898397..412b28a 100644
--- a/bumble/profiles/asha_service.py
+++ b/bumble/profiles/asha_service.py
@@ -19,6 +19,8 @@
 import struct
 import logging
 from typing import List
+
+from bumble import l2cap
 from ..core import AdvertisingData
 from ..device import Device, Connection
 from ..gatt import (
@@ -149,7 +151,10 @@ class AshaService(TemplateService):
             channel.sink = on_data
 
         # let the server find a free PSM
-        self.psm = self.device.register_l2cap_channel_server(self.psm, on_coc, 8)
+        self.psm = device.create_l2cap_server(
+            spec=l2cap.LeCreditBasedChannelSpec(psm=self.psm, max_credits=8),
+            handler=on_coc,
+        ).psm
         self.le_psm_out_characteristic = Characteristic(
             GATT_ASHA_LE_PSM_OUT_CHARACTERISTIC,
             Characteristic.Properties.READ,
diff --git a/bumble/rfcomm.py b/bumble/rfcomm.py
index 4002dc7..53e98e0 100644
--- a/bumble/rfcomm.py
+++ b/bumble/rfcomm.py
@@ -898,8 +898,8 @@ class Client:
     async def start(self) -> Multiplexer:
         # Create a new L2CAP connection
         try:
-            self.l2cap_channel = await self.device.l2cap_channel_manager.connect(
-                self.connection, RFCOMM_PSM
+            self.l2cap_channel = await self.connection.create_l2cap_channel(
+                spec=l2cap.ClassicChannelSpec(RFCOMM_PSM)
             )
         except ProtocolError as error:
             logger.warning(f'L2CAP connection failed: {error}')
@@ -936,7 +936,9 @@ class Server(EventEmitter):
         self.acceptors = {}
 
         # Register ourselves with the L2CAP channel manager
-        device.register_l2cap_server(RFCOMM_PSM, self.on_connection)
+        device.create_l2cap_server(
+            spec=l2cap.ClassicChannelSpec(psm=RFCOMM_PSM), handler=self.on_connection
+        )
 
     def listen(self, acceptor: Callable[[DLC], None], channel: int = 0) -> int:
         if channel:
diff --git a/bumble/sdp.py b/bumble/sdp.py
index 01e72da..ae01301 100644
--- a/bumble/sdp.py
+++ b/bumble/sdp.py
@@ -766,8 +766,9 @@ class Client:
         self.channel = None
 
     async def connect(self, connection: Connection) -> None:
-        result = await self.device.l2cap_channel_manager.connect(connection, SDP_PSM)
-        self.channel = result
+        self.channel = await connection.create_l2cap_channel(
+            spec=l2cap.ClassicChannelSpec(SDP_PSM)
+        )
 
     async def disconnect(self) -> None:
         if self.channel:
@@ -933,7 +934,9 @@ class Server:
         self.current_response = None
 
     def register(self, l2cap_channel_manager: l2cap.ChannelManager) -> None:
-        l2cap_channel_manager.register_server(SDP_PSM, self.on_connection)
+        l2cap_channel_manager.create_classic_server(
+            spec=l2cap.ClassicChannelSpec(psm=SDP_PSM), handler=self.on_connection
+        )
 
     def send_response(self, response):
         logger.debug(f'{color(">>> Sending SDP Response", "blue")}: {response}')
diff --git a/examples/run_a2dp_sink.py b/examples/run_a2dp_sink.py
index b20f0d6..61bdce3 100644
--- a/examples/run_a2dp_sink.py
+++ b/examples/run_a2dp_sink.py
@@ -131,7 +131,7 @@ async def main():
             await device.power_on()
 
             # Create a listener to wait for AVDTP connections
-            listener = Listener(Listener.create_registrar(device))
+            listener = Listener.for_device(device)
             listener.on('connection', on_avdtp_connection)
 
             if len(sys.argv) >= 5:
diff --git a/examples/run_a2dp_source.py b/examples/run_a2dp_source.py
index 2443518..69dc2d0 100644
--- a/examples/run_a2dp_source.py
+++ b/examples/run_a2dp_source.py
@@ -179,7 +179,7 @@ async def main():
                 await stream_packets(read, protocol)
             else:
                 # Create a listener to wait for AVDTP connections
-                listener = Listener(Listener.create_registrar(device), version=(1, 2))
+                listener = Listener.for_device(device=device, version=(1, 2))
                 listener.on(
                     'connection', lambda protocol: on_avdtp_connection(read, protocol)
                 )
diff --git a/examples/run_asha_sink.py b/examples/run_asha_sink.py
index 3e4955d..2d6f0d5 100644
--- a/examples/run_asha_sink.py
+++ b/examples/run_asha_sink.py
@@ -21,6 +21,7 @@ import sys
 import os
 import logging
 
+from bumble import l2cap
 from bumble.core import AdvertisingData
 from bumble.device import Device
 from bumble.transport import open_transport_or_link
@@ -95,8 +96,10 @@ async def main():
 
             channel.sink = on_data
 
-        psm = device.register_l2cap_channel_server(0, on_coc, 8)
-        print(f'### LE_PSM_OUT = {psm}')
+        server = device.create_l2cap_server(
+            spec=l2cap.LeCreditBasedChannelSpec(max_credits=8), handler=on_coc
+        )
+        print(f'### LE_PSM_OUT = {server.psm}')
 
         # Add the ASHA service to the GATT server
         read_only_properties_characteristic = Characteristic(
@@ -147,7 +150,7 @@ async def main():
             ASHA_LE_PSM_OUT_CHARACTERISTIC,
             Characteristic.Properties.READ,
             Characteristic.READABLE,
-            struct.pack('<H', psm),
+            struct.pack('<H', server.psm),
         )
         device.add_service(
             Service(
diff --git a/tests/a2dp_test.py b/tests/a2dp_test.py
index 92f7915..ca59890 100644
--- a/tests/a2dp_test.py
+++ b/tests/a2dp_test.py
@@ -185,7 +185,7 @@ async def test_source_sink_1():
         sink.on('rtp_packet', on_rtp_packet)
 
     # Create a listener to wait for AVDTP connections
-    listener = Listener(Listener.create_registrar(two_devices.devices[1]))
+    listener = Listener.for_device(two_devices.devices[1])
     listener.on('connection', on_avdtp_connection)
 
     async def make_connection():
diff --git a/tests/l2cap_test.py b/tests/l2cap_test.py
index c6b2340..5cb285c 100644
--- a/tests/l2cap_test.py
+++ b/tests/l2cap_test.py
@@ -22,7 +22,11 @@ import random
 import pytest
 
 from bumble.core import ProtocolError
-from bumble.l2cap import L2CAP_Connection_Request
+from bumble.l2cap import (
+    L2CAP_Connection_Request,
+    ClassicChannelSpec,
+    LeCreditBasedChannelSpec,
+)
 from .test_utils import TwoDevices
 
 
@@ -80,7 +84,9 @@ async def test_basic_connection():
 
     # Check that if there's no one listening, we can't connect
     with pytest.raises(ProtocolError):
-        l2cap_channel = await devices.connections[0].open_l2cap_channel(psm)
+        l2cap_channel = await devices.connections[0].create_l2cap_channel(
+            spec=LeCreditBasedChannelSpec(psm)
+        )
 
     # Now add a listener
     incoming_channel = None
@@ -95,8 +101,12 @@ async def test_basic_connection():
 
         channel.sink = on_data
 
-    devices.devices[1].register_l2cap_channel_server(psm, on_coc)
-    l2cap_channel = await devices.connections[0].open_l2cap_channel(psm)
+    devices.devices[1].create_l2cap_server(
+        spec=LeCreditBasedChannelSpec(psm=1234), handler=on_coc
+    )
+    l2cap_channel = await devices.connections[0].create_l2cap_channel(
+        spec=LeCreditBasedChannelSpec(psm)
+    )
 
     messages = (bytes([1, 2, 3]), bytes([4, 5, 6]), bytes(10000))
     for message in messages:
@@ -138,10 +148,13 @@ async def transfer_payload(max_credits, mtu, mps):
 
         channel.sink = on_data
 
-    psm = devices.devices[1].register_l2cap_channel_server(
-        psm=0, server=on_coc, max_credits=max_credits, mtu=mtu, mps=mps
+    server = devices.devices[1].create_l2cap_server(
+        spec=LeCreditBasedChannelSpec(max_credits=max_credits, mtu=mtu, mps=mps),
+        handler=on_coc,
+    )
+    l2cap_channel = await devices.connections[0].create_l2cap_channel(
+        spec=LeCreditBasedChannelSpec(server.psm)
     )
-    l2cap_channel = await devices.connections[0].open_l2cap_channel(psm)
 
     messages = [bytes([1, 2, 3, 4, 5, 6, 7]) * x for x in (3, 10, 100, 789)]
     for message in messages:
@@ -189,8 +202,12 @@ async def test_bidirectional_transfer():
     def on_client_data(data):
         client_received.append(data)
 
-    psm = devices.devices[1].register_l2cap_channel_server(psm=0, server=on_server_coc)
-    client_channel = await devices.connections[0].open_l2cap_channel(psm)
+    server = devices.devices[1].create_l2cap_server(
+        spec=LeCreditBasedChannelSpec(), handler=on_server_coc
+    )
+    client_channel = await devices.connections[0].create_l2cap_channel(
+        spec=LeCreditBasedChannelSpec(server.psm)
+    )
     client_channel.sink = on_client_data
 
     messages = [bytes([1, 2, 3, 4, 5, 6, 7]) * x for x in (3, 10, 100)]
diff --git a/web/speaker/speaker.py b/web/speaker/speaker.py
index d9293a4..d9488ce 100644
--- a/web/speaker/speaker.py
+++ b/web/speaker/speaker.py
@@ -296,7 +296,7 @@ class Speaker:
         self.device.on('key_store_update', self.on_key_store_update)
 
         # Create a listener to wait for AVDTP connections
-        self.listener = Listener(Listener.create_registrar(self.device))
+        self.listener = Listener.for_device(self.device)
         self.listener.on('connection', self.on_avdtp_connection)
 
         print(f'Speaker ready to play, codec={self.codec}')